An immobile tablet user tries Octa's Monkey Kit. This is sooo different from using a laptop.

Stop me if you've heard this one: Two guys are sitting in a Starbucks. One is tapping away on his Macbook Air. The guy next to him is busy pecking as well, on a keyboard attached to his iPad.

Yet only one of these two are considered to be on a "mobile" device.

If this were an isolated incident, you could conclude that yes, sometimes, the way we use tablets and laptops are pretty similar. It's not. Study after study shows that only a small minority of tablet owners connect them to cellular networks. That means most of the time most are employing them within Wi-fi range. Translation: They're using them on their couch, often in a reclining position.

Illogically, tablet activity is usually lumped in with phones anyway. For instance, a report Monday from Forrester Research estimated that U.S. mobile commerce sales will hit $114 billion this year. Of that, $38 billion will come from mobile phones.

That's still a lot, but take tablets out of the equation and the figure is two-thirds less impressive.

Better to include tablet-based commerce in overall e-commerce sales where they belong. In my personal experience, I use my laptop and tablet pretty much interchangeably at home. If I'm on my tablet and get the urge to buy something (usually an ebook from Amazon), I do it on my iPad. If I'm on my laptop, I'll use that. I prefer the latter because it's much easier to type on a laptop. Sometimes I'm too damn lazy to get up and look for my Macbook Air though.

As a result, my m-commerce activities are completely random. If you were tracking my activity, you might see a big spike in tablet purchases one month and then a precipitous downturn the next, based entirely on my couch positioning relative to the proximity of my laptop. The end result is the same, though: I visited a website and bought something.

Yes, that's right, a website. Perhaps I'm unusual in this regard. A recent Nielsen study found that 81% of tablet use is on apps, rather than the mobile web:

On second thought, no. I think my tablet use is actually pretty normal. Most of the time I use my iPad Mini to read ebooks on Kindle or magazines on Newsstand or to play Scrabble. Probably roughly 20% of the time I'm using Safari to browse the web. That's how I've completed all of my tablet-based purchases until now. Even though I buy a lot of stuff from Amazon, I haven't downloaded the app yet.

I may be in minority for tablet-based purchases, though. The reason Forrester and others consider such transactions "mobile" has nothing to do with mobility and everything to do with the way you bought your item. If you used an app or a mobile version of the retailer's site, then it was a mobile transaction.

In reality, the purchase was made using an interface different from a desktop, but it was essentially the same. As more mobile apps migrate to desktop and visa versa, such distinctions become increasingly dubious. The false dichotomy makes drains the word "mobile" of all meaning.

That's especially true if you contrast a tablet with a truly mobile device, the smartphone. Personally, I almost never use the browser on my phone unless I'm desperate to track down some vital information, like the answers to that day's New York Times crossword puzzle or the words that make up the STEM acronym (two recent searches.) I think I've used my phone maybe once to buy something. If I recall, I was stuck somewhere boring for a few hours without my iPad.

Again, here I'm fairly normal. As Sucharita Mulpuru, the author of Forrester's report notes, consumers who actually buy things on their phones or tablets are outliers. Most people don't or haven't.

That doesn't mean they never will. At some point, it might make sense to buy a lot of things on my phone, but I can't really see a scenario in which that might be the case. Maybe mobile commerce technology will catch on to the point that eventually I'll use my phone to make most of my purchases. That's a case of swapping my wallet for a phone, though, not replacing my PC as a vehicle for ecommerce.

When that comes to pass, we can debate whether mobile commerce has really arrived. Until then we shouldn't buy in to this idea of larding m-commerce stats with tablet sales.